Composite material made from a substrate material and a barrier layer material

ABSTRACT

A composite material having a substrate material and at least one barrier coating on one side of the substrate material. The barrier coating is plasma impulse chemical vapor deposited (PICVD) to the substrate material. The barrier coating includes at least one of material selected from the group consisting of SiO x , TiO x , SnO x , Si 3 N y , Nb 2 O y , and Al 2 O y .

[0001] The invention relates to a composite material having a substratematerial and at least one barrier coating applied to one side of thesubstrate material, and to a process for producing a composite materialcomprising a substrate material and at least one barrier coating.

[0002] To reduce the permeation of gases and liquids in the field ofplastic packaging and to protect the plastic material from chemicalattack or UV radiation, it is advantageous for substrate materials, inparticular plastic substrates, to be provided with a barrier coating.Barrier coatings allow the same property to be achieved with inexpensivebulk plastics as with expensive specialty plastics and make it possibleto replace glass, for example, in the field of pharmaceutical packagingmaterials with bulk plastics of this type. Applications of barriercoatings to a plastic substrate have been disclosed by the followingapplications:

[0003] U.S. Pat. No. 5,798,139

[0004] U.S. Pat. No. 5,833,752

[0005] U.S. Pat. No. 6,001,429

[0006] U.S. Pat. No. 5,798,139 describes the production of plasticcontainers with a carbon film coating. The carbon film is intended toform a gas barrier and to solve the problem of sorption from the plasticmaterial.

[0007] U.S. Pat. No. 5,833,752 has disclosed a system in which thebarrier coating is applied from a plasma. The energy used to maintainthe plasma is applied by devices which are distinguished by the factthat the energy is introduced into the interior of the containers to becoated via an outer electrode.

[0008] U.S. Pat. No. 6,001,429 again discloses the application of abarrier layer to the inner surface of a plastic substrate, with HMDSO asmonomer gas together with an oxygen carrier gas being passed into theinterior of the item which is to be coated.

[0009] It is an object of the invention, working on the basis of U.S.Pat. No. 5,833,752 and/or U.S. Pat. No. 6,001,429, to provide acomposite material and a process for producing a composite material ofthis type which is distinguished by an improved barrier action andimproved bonding to the plastic material.

[0010] According to the invention, the object is achieved by a compositematerial as described in claim 1 and a process as described in claim 18.The inventors have discovered that by using a plasma-enhanced CVDprocess, a so-called PICVD process, the required good bonding isachieved, and so is excellent barrier action with respect to substancesfrom the atmosphere, substances contained in the plastic or substancesreleased from the plastic, as well as substances which are in contactwith the surface of the composite material. In particular, the use of aPICVD process makes it possible to use surface temperatures of typically50 to 150° C., i.e. thermally sensitive plastics can be provided with anexcellent barrier coating without damage to the plastic surface. Verythin layers, even down to monomolecular layers, with barrier propertiescan be applied to a substrate material with the aid of the PICVDprocessors. This allows a considerable saving on materials. Furthermore,layers of this type are distinguished by a high degree of flexibility.

[0011] The use of a PICVD process also makes it possible to employmulti-position installations, which in particular leads to a highthroughput.

[0012] According to the invention, the barrier coating comprises atleast one of the following materials: SiO_(x) with xε[0,2], TiO_(x) withxε[0,2], amorphous hydrocarbons, electrically conductive layers, SnO_(x)with xε[0,2], Si_(x)N_(y) with xε[0,3] or xε[0,1], yε[0,4], Nb_(x)O_(y)with xε[0,2], yε[0,5], Al_(x)O_(y) with xε[0,2], yε[0,3].

[0013] Moreover, particularly good barrier actions can be achieved witha barrier coating on at least one side of the substrate material whichis applied by means of plasma impulse chemical vapor deposition (PICVD)and comprises at least one of the following materials:

[0014] SiO_(x) with x<2, in particular with 1.7≦x<2;

[0015] SiO_(x) with x>2, in particular with 2≦x≦2.5;

[0016] TiO_(x) with x<2, in particular with 1.7≦x<2;

[0017] TiO_(x) with x>2, in particular with 2<x≦2.5;

[0018] SnO_(x) with x<2, in particular with 1.7≦x<2;

[0019] SnO_(x) with x>2, in particular with 2<x≦2.5;

[0020] Si₃N_(y) with y<4, in particular with 3.5<y<4;

[0021] Si₃N_(y) with y>4, in particular with 4<y<4.5;

[0022] Nb₂O_(y) with y<5, in particular with 4<y<5;

[0023] Nb₂O_(y) with y>5, in particular with 5<y<6;

[0024] Al₂O_(y) with y<3, in particular with 2.5<y<3;

[0025] Al₂O_(y) with y>3, in particular with 3<y<3.5.

[0026] Slightly substoichiometric or superstroichiometric layercompositions of this type result in very dense and compact layerstructures with long diffusion paths.

[0027] The barrier coating may also particularly advantageously have acomposition or structure which varies perpendicular to the coatedsurface of the substrate. The variation may in this case be continuousor stepped. A stepped variation results in a multilayer barrier coating.By way of example, the bottom layer, which is in contact with thesurface of the substrate, can be used as a bonding layer for thesubsequent coatings. Layers of this type may, for example, be producedby a continuous or stepped change in the precursor content in theprocess gas during the coating operation.

[0028] Barrier coatings of this type may, for example, comprisealternating layers, such as for example an alternating TiO_(x)/SiO_(x)layer. In this case, the TiO_(x) layer is preferably in contact with thesubstrate. By way of example, the individual layers of the alternatinglayer can be produced with a thickness of from 5 nm to 100 nm. Aparticularly good barrier action can be achieved with an approximately100 nm thick layer. To achieve a high throughput and therefore toimprove the process economics, however, coatings with lower layerthickness are also advantageous.

[0029] Particularly good coating properties can in this case also beachieved with multiple alternating layers. A multiple alternating layerof this nature may, for example, comprise an alternatingTiO_(x)/SiO_(x)/TiO_(x)/SiO_(x)/layer. Alternating layers of this typemay particularly advantageously be used for the coating of films,including for coating on both sides. Films, since they generally haveonly a low material thickness, have only a poor barrier action, andconsequently the good barrier action of the alternating layersnevertheless ensures that diffusion rates through the film are low.

[0030] The plastic substrate preferably comprises one or more of thefollowing materials: polycyclic hydrocarbons, polycarbonates,polyethylene terephthalates, polystyrene, polyethylene, in particularHDPE, polypropylene, polymethyl methacrylate, PES. In particular, it ispossible, as a result of application by means of a PICVD process, tocoat polycyclic hydrocarbons, such as COC, which themselves alreadyrepresent a high-density barrier plastic, in such a manner that thishigh-density barrier plastic is protected from attack by organicsubstances, in particular fats or greases.

[0031] In a preferred embodiment, the thickness of the barrier coatingis <1000 nm, preferably <300 nm. In addition to good barrier properties,barrier layers of this type are also highly flexible. Furthermore, withsuch thin layers it is in particular also possible to avoid intrinsicstresses which can cause the barrier layer to flake off. In aparticularly preferred embodiment, the barrier layer has still furtheradditional functions, for example optical or electrical functions ornonscratch or antireflection functions. By way of example, an opticalinterference coating which simultaneously acts as a barrier layer can beused in organic LEDs, known as OLEDs, or in the field of photovoltaiccells.

[0032] However, with the invention it is also possible to produce verymuch thinner layers. Barrier coatings of this type may have thicknessesof from 5 nm, preferably from 15 nm, in particular from 20 nm.

[0033] In addition to the composite material, the invention alsoprovides a process for producing a composite material of this type,which is distinguished by the fact that in a coating reactor a plasma isgenerated by means of a pulse, with the result that precursor gaseswhich are introduced into the reactor react with the gas atmosphere inthe coating reactor and are deposited on the substrate material for abarrier coating. Transparent barrier layers result if the followingprecursor materials are used: HMDSN, HMDSO, PMS, silane in N₂, TiCl₄ inan atmosphere comprising O₂, N₂, N₂+NH₃. Materials of this type allowTiO₂, SiO₂ and Si_(x)N_(y) barrier layers to be deposited on variousplastic materials. A TiO₂ barrier layer is deposited, for example, if aTiCl₄ precursor gas in an O₂ atmosphere is used, while an SiO₂ barrierlayer is deposited when a HMDSN precursor gas in an O₂ atmosphere isused, and an Si—N barrier layer is deposited if an SiH₄ or TMS precursorin an N₂+NH₃ atmosphere is used.

[0034] In this case, the coating reactor is advantageously evacuatedafter the substrate material has been introduced into the coatingreactor and before precursor gases are introduced. This means that thereis no need to provide a lock arrangement for transferring the substrateswhich are to be coated from atmospheric pressure into an evacuatedreactor.

[0035] The substrate material which is to be coated may in particularalso comprise a hollow body. Therefore, the process according to theinvention allows a coating to be deposited on the inner side and/orouter side of the hollow body. In the case of internal coating, it isalso advantageous for the area surrounding the hollow body to beevacuated to a pressure of less than 200 mbar, preferably between 10 and100 mbar, prior to the coating, and at the same time for the interior ofthe hollow body to be evacuated to a base pressure of less than 1 mbar,preferably between 0.3 and 0.05 mbar, so that the walls of the hollowbody are not coated on by large pressure differences, which, in the caseof thin-walled material, could lead to deformation of the hollow body.Furthermore, to coat exclusively the inner side, the external pressureis advantageously selected in such a way that no plasma is ignited inthe outside space. To avoid large pressure differences even during theevacuation process, it is in this case advantageously possible initiallyto evacuate uniformly, in such a way that the external pressurementioned above is reached, and then for just the inside to be evacuatedfurther to a base pressure of less than 1 mbar, preferably between 0.05and 0.3 mbar.

[0036] The O₂ permeability is determined in accordance with DIN 53380,the content of disclosure of which is hereby incorporated in itsentirety in the present application. According to DIN 53380, in the caseof films the specimen is clamped in a gastight manner between the twoparts of the permeation chamber. Nitrogen flows slowly through one partof the chamber, while oxygen flows slowly through the other part of thechamber. The oxygen which migrates through the film into the nitrogencarrier gas is transported to an electrochemical sensor, where theoxygen produces an electrical current intensity which is proportional tothe quantitative flow of oxygen.

[0037] If hollow bodies are tested, the nitrogen carrier gas stream ispassed directly through the hollow body. The oxygen acts on the hollowbody from the outside.

[0038] In particular the TiO₂ barrier layer and the SiO₂ barrier layer,which have been produced by means of a PICVD process in the mannerdescribed above, are distinguished by particularly good barrierproperties. For example, the oxygen permeation and also the water vaporpermeation through the coated materials are significantly increased bythe barrier coating compared to the uncoated substrate material, asshown in the table below. Also, the coating of SiO₂ on polycarbonate hasa high resistance to solvents. The barrier action is given as BIF inTable 1. BIF is in this case the quotient of the measured O₂ or watervapor permeability of the uncoated body/O₂ or water vapor permeabilityof the coated body.

[0039] The water vapor permeability of the uncoated and coated bodies isdetermined in accordance with DIN 53122, the content of disclosure ofwhich is hereby incorporated in its entirety in the present application.In accordance with DIN 53122, a dish holding absorption agent is closedoff by the specimen using wax and stored in a humid atmosphere.

[0040] The quantity of water vapor which passes through the specimen iscalculated from the increase in the weight of the dish as soon as thisincrease becomes linear when plotted against time.

[0041] The microwave power range which is favorable for good-qualitycoatings is in this case between 300 W and 12 kW, in particular between600 W and 11 kW pulse power.

[0042] The invention is to be explained in more detail below withreference to the exemplary embodiment and the figures, in which:

[0043]FIG. 1 shows a PICVD coating station for a hollow body,

[0044]FIG. 2 shows a PICVD coating station for a film.

[0045] TABLE 1 Action of the barrier coating Water vapor O₂ Thicknessresistance resistance Solvent Material Coating [nm] [BIF] [BIF]resistance COC SiO₂ 20-100 3 >10 PC SiO₂ 20-100 3 >24 Acetone >10 minPET SiO₂ 20-100 2 >20 SiO₂ 20-100 >50 2 × TiO₂ 20-100 >10  >10² PES 2 ×Si₂ 20-100 >6 × 10² >6 × 10² HDPE 20-100 >10 PP SiO₂ 20-100  >2

[0046] The text which follows is intended to provide an exemplaryembodiment of the invention, in which polycarbonate has been selected assubstrate material in the form of a hollow body. The polycarbonatehollow body was provided with an O₂/H₂O barrier layer in accordance withthe invention. The bottles were coated at a PICVD coating station forglass bottles, as described in similar form, for example, in U.S. Pat.No. 5,736,207, the content of the disclosure of which is herebyincorporated in the present application. The apparatus used for thecoatings differs from the apparatus disclosed by U.S. Pat. No. 5,736,207in terms of the size of the receivable substrates which are to becoated. In the apparatus used for the coating in accordance with theinvention, it is possible to receive and coat substrates with a volumeof up to 5000 ml. An embodiment of a coating station of this type for 3Dbodies, for example bottles or vials, is shown in FIG. 1. The coatingstation shown in FIG. 1 comprises a vacuum apparatus 1, a gas generator3 and a microwave generator 5 for generating microwaves which in turngenerate a plasma for a predetermined time in the coating reactor, whichin the present case is formed by the 3D hollow body 7 which is to becoated. Furthermore, the coating station comprises a receiving device 9for holding the 3D hollow body 7 which is to be coated on the inside. Ina first embodiment, the 3D hollow bodies 7 can only be evacuated on theinside. To avoid mechanical deformation during the coating operation, itis also possible for the space outside the hollow body which is to becoated to be evacuated. For this purpose, an evacuable receptacle 11 isarranged around the 3D hollow body 7. A structure of this type resultsin the possibility of carrying out an external coating as an alternativeto or at the same time as the internal coating.

[0047] The 3D hollow body and/or receptacle is evacuated using vacuumpump devices in accordance with the prior art. The volume which isenclosed by the hollow body and is to be evacuated is in this casepreferably in a range from 10 ml to 5000 ml, in particular in a rangefrom 50 ml to 2000 ml.

[0048] The 3D hollow body is evacuated via vacuum line 13, and thereceptacle 11 is evacuated via vacuum line 15. To enable the receptacle11 optionally to be evacuated in addition to the interior of the 3Dhollow body, a valve 17 is provided. As mentioned above, in the presentexemplary embodiment the inner wall 19 of the 3D hollow body 7 itselfforms the actual coating chamber. Following the evacuation of theinterior of the 3D hollow body 7, the interior of the hollow body isfilled with a precursor gas, for example with a mixture of HMDSN orHMDSO and oxygen, via feedline 21, the concentration of HMDSO/HMDSNlying, for example, in the range between 1 and 10% of the oxygen flow.As an option for the introduction of the precursor gas and oxygen intothe interior of the 3D hollow body 7 which is to be coated, it ispossible for precursor gas and oxygen to be passed into the receptacle11 via feedline 23 for external coating. Once again, a valve 25 isarranged in the feedline 23. After the filling step, the pressure in thecoating reactor is between 1.2 and 0.2 mbar. After the evacuation,microwave power is introduced into the 3D hollow body 7 which is to becoated and/or the receptacle 11. The introduction of the microwave powerby the microwave generator 5, which may, for example, be a magnetron,into the receptacle or 3D hollow body is performed via a dielectricwindow 27 arranged above the 3D hollow body 7. Other ways of introducingthe microwave power, for example via antennas, would be possible. Apulsed plasma is generated inside the hollow body with the aid of themicrowave power which is supplied and is preferably time-modulated.Typical pulse lengths are between 0.1 and 20 ms, with an interpulseperiod in the range from 5 to 400 ms. The advantages of coating with theaid of pulses in accordance with the invention lie in the low thermalload on the plastic substrate. Furthermore, full gas exchange can becarried out during the interpulse periods, so that the gas compositionis always ideal at the start of the next microwave pulse. Theabovementioned parameter ranges for pulse length and interpulse periodhave proven particularly favorable in order to ensure good gas exchangecombined, at the same time, with a low thermal load and rapid layergrowth. The results of the hollow bodies which have been coated usingthe process described above are summarized in the table below: TABLE 2Internally coated polycarbonate bottles with an O₂/H₂O barrier, layerthickness: 100 nm Mean Inter- MW Barrier Barrier O₂ Pulse pulse powerimprovement improvement Pressure Flow HMDSN length period (pulse factorfactor [mbar] rate [sccm] [ms] [ms] power) H₂O O₂ 1-0.3 200-50 5-0.12.0-0.5 50-10 100 W-200 W 3 2-20 (2.0 kw-4.0 kW

[0049] As an alternative to coating 3D hollow bodies, according to theinvention it is also possible to coat sheet-like substrates, for examplefilms, or panels. Substrates in panel form may, for example, be displaycovers for LCD displays. In this context, the barrier coatings may alsoprovide further functional properties, such as for exampleantireflection properties or a nonscratch coating.

[0050]FIG. 2 shows a coating device for bodies of this type. Componentswhich are identical to those shown in FIG. 1 are provided with the samereference symbols. Unlike in FIG. 1, the object which is to be coateddoes not itself form the coating chamber, but rather it is held in areceptacle 11 by means of a holder 30. The holder 30 comprises gasoutlets 32 from which precursor gas and oxygen are passed into thereceptacle 11 after the receptacle has been evacuated via line 34. Aplasma is ignited inside the receptacle 11 by means of the microwavepower which is introduced on both sides of the receptacle via dielectricwindows 27.1, 27.2, and the substrate 36 is coated. The microwave poweris preferably pulsed.

[0051] The advantage of plasma excitation with the aid of microwaves,i.e. a frequency of 90-3000 MHz, in particular 300-2500 MHz, compared toexcitation with radio frequency (RF) as in the prior art, is inparticular the thinner edge layer which is formed with microwaveexcitation. In a thin edge layer, the ions of the plasma can only absorba small amount of energy, and consequently they only possess a lowkinetic energy when they make contact with the substrate which is to becoated, and thereby can only cause minor damage, for example as a resultof introduction of heat or charging. is On account of these advantages,the plasma generated using microwaves can be operated with significantlyhigher powers and higher pressures than in the prior art, resulting inadvantages, for example, in the deposition rate.

[0052] Excitation using pulsed radio frequency may also, however, beadvantageous for various applications, for example in order to generatemore homogeneous field distributions in the plasma and thereforeparticularly uniform coatings in the case of a long wavelength. In thiscontext, the frequency range below 90 MHz, in particular in the rangefrom 10 MHz to 90 MHz, is appropriate.

[0053] The invention for the first time provides a composite materialwith improved barrier properties as well as a process for producing amaterial of this nature.

[0054] The invention is to be explained in more detail below on thebasis of the exemplary embodiments:

[0055] Exemplary Embodiment 1:

[0056] A bottle made from polyethylene terephthalate (PET) with a volumeof 0.5 l is simultaneously evacuated on the outside to a pressure of 85mbar and on the inside initially to a base pressure of less than 0.09mbar. Subsequently, a mixture of oxygen and hexyamethyldisilazane(HMDSN) is passed into the interior of the bottle at a pressure of 0.3mbar. Then, pulsed microwave energy with a pulse power of 5 kW and afrequency of 2.45 GHz is introduced and a plasma is ignited in thecontainer. The coating is carried out with a growth rate ofapproximately 0.89 nm layer thickness growth per second.

[0057] a) Oxygen and Water Vapor Barrier:

[0058] Over the course of 90 seconds, the container is internally coatedwith 80 nm of SiO_(x). This corresponds to a growth rate of 0.89 nm/s.Immediately afterward, the bottle is ventilated and removed.Measurements carried out to test the water vapor permeation inaccordance with DIN 53122, Part 1 using a gravimetric measurement methodgive a value of 14.3 mg/(specimen×day) for the coated bottle, whereas awater vapor permeation of 28.0 mg/(specimen×day) is measured for theuncoated bottle. This gives a barrier improvement factor (BIF) of 2.0.Measurements carried out on the oxygen permeability in accordance withDIN 53380-3 using an electrochemical sensor give a value of 0.018cm³/(specimen×day×bar) for the coated bottle and a value of 0.15cm³/(specimen×day×bar) for the uncoated bottle, and therefore the O₂ BIFis 8.3.

[0059] b) Oxygen and Water Vapor Barrier in a Short Coating Time:

[0060] An internal coating of SiO_(x) in a layer thickness of 20 nm iscarried out within 18 seconds, corresponding to a deposition rate ofapproximately 1.1 nm/s. The container is then flooded with gas andremoved from the apparatus. Measurements carried out on the water vaporpermeation give a value of 25.3 mg/(specimen×day) for the coated bottle.This gives a H₂O BIF of 1.1. Measurements carried out on the oxygenpermeability give a value of 0.036 cm³ (specimen×day×bar), andconsequently the O₂ BIF is 4.

[0061] c) Oxygen Barrier Within a Very Short Coating Time, Low Heating:

[0062] The inside of the bottle is coated with SiO_(x) in a layerthickness of 10 nm within 9 seconds. The container is then flooded withgas and removed from the apparatus. Measurements carried out on theoxygen permeability give a value of 0.062 cm³/(specimen×day×bar) andtherefore an O₂ BIF of 2. The short coating time means that the specimenis only heated slightly.

[0063] d) Controlling the Heating Rate by Pulse Length and InterpulsePeriod:

[0064] By suitably selecting the pulse length and interpulse period, itis possible to have a deliberate influence on the heating of thespecimens during the coating. At a microwave power of 1000 W with pulselengths of 0.5 ms and interpulse periods of 200 ms, it is possible toachieve heating rates of less than 0.3° C./s. This is advantageous inparticular for coating plastics, since many plastics, such as forexample PET, are deformed and crystallized even at temperatures over 80°C., with the result that cracks may form in the layer or the layer mayflake off from the plastic substrate.

[0065] Exemplary Embodiment 2:

[0066] High Oxygen Barrier at Low Microwave Power:

[0067] A 0.5 l bottle made from polyethylene terephthalate (PET) issimultaneously evacuated on the outside to a pressure of 85 mbar and onthe inside initially to a base pressure of less than 0.09 mbar.Subsequently, a mixture of oxygen and hexamethyldisilazane (HMDSN) ispassed into the interior of the bottle at a pressure of 0.4 mbar. Then,pulsed microwave energy with a pulse power of 1000 W and a frequency of2.45 GHz is introduced, so that a plasma is ignited in the container.

[0068] A 100 nm thick single layer of SiO_(x) is applied in 98.4seconds, corresponding to a deposition rate of approximately 1 nm/s.Then, the specimen is flooded with nitrogen and removed. Measurementscarried out on the water vapor permeation give a value of 18.7mg/(specimen×day) for a coated bottle and 22.5 mg/(specimen×day) for anuncoated bottle. This means that the H₂O BIF is 1.2. The oxygenpermeation is 0.0015 cm³/(specimen×day×bar) for an uncoated bottle and0.18 cm³/(specimen×day×bar) for an uncoated bottle, giving an O₂ BIF of82.

[0069] Exemplary Embodiment 3: Double Layer with Improved Bonding:

[0070] Variant 1:

[0071] A substrate, for example a 0.5 l bottle made from polyethyleneterephthalate (PET) is simultaneously evacuated on the outside to apressure of 85 mbar and on the inside initially to a base pressure ofless than 0.09 mbar. Subsequently, first of all a mixture of oxygen andhexamethyldisilazane (HMDSN) with a high precursor content which amountsto 10% of the O₂ flow is introduced into the interior of the bottle at apressure of 0.4 mbar. Then, pulsed microwave energy with a pulse powerof 1000 W and a frequency of 2.45 GHz is introduced, so that a plasma isignited in the container. A layer with a thickness of 5-25 nm is appliedand acts as a bonding agent between plastic and barrier layer but alsomay have a slight barrier action with respect to gases. Immediatelythereafter, a mixture of oxygen and hexamethyldisilazane (HMDSN) with alow precursor content amounting to ≦2% of the oxygen flow rate flowsinto the container. Once again, a pulsed microwave plasma is ignited anda second layer is applied, with a thickness of between 25 and 45 nm.This layer has a high barrier action against gases.

[0072] Variant 2, Internal Coating of a 0.51 l PET Bottle (WallThickness 0.5 mm) with a Bonding Agent/Barrier Composite with ImprovedBonding:

[0073] A bottle made from polyethylene terephthalate (PET) with a volumeof 0.5 l is simultaneously evacuated to a pressure of 85 mbar on theoutside and initially to a base pressure of less than 0.1 mbar on theinside. Subsequently, a mixture of oxygen and hexamethyldisilazane(HMDSN) is passed into the interior of the bottle at a pressure of 0.3mbar. Then, pulsed microwave energy with a pulse power of 1000 watts anda frequency of 2.45 GHz is introduced and a plasma is ignited in thecontainer.

[0074] i) Firstly, as in Variant 1, an organic bonding agent layer isapplied, but this time in a thickness of 100 nm at a high HMDSNconcentration.

[0075] ii) This is followed by a rapid gas change to a lower HMDSNconcentration of 2%, and an inorganic barrier layer with a layerthickness of 50 nm is applied over the course of 26 seconds,corresponding to a rate of 1.9 nm/s.

[0076] The coating makes it possible to produce a bonding agent/barriercomposite with a high O₂ barrier improvement factor (O₂ BIF) ofsignificantly over 40.

[0077] The permeation through the uncoated bottle is 0.125cm³/(specimen×day×bar), and that through the coated bottle issignificantly below 0.003 cm³/(specimen×day×bar).

[0078] The resolution limit of the Mocon-Oxtran measurement applianceused was then reached.

[0079] Variant 3, Internal Coating of a 0.4 l PET Bottle (WallThickness: 0.4 mm) with a Bonding Agent/Barrier Composite, ComparisonBetween Barrier/Bonding Agent Composite and Pure Barrier Layer:

[0080] A bottle made from polyethylene terephthalate (PET) with a volumeof 0.4 l is simultaneously evacuated to a pressure of 85 mbar on theoutside and initially to a base pressure of less than 0.1 mbar on theinside. Subsequently, a mixture of oxygen and hexamethyldisilazane(HMDSN) is passed into the interior of the bottle at a pressure of 0.3mbar. Then, pulsed microwave energy with a pulse power of 1000 watts anda frequency of 2.45 GHz is introduced and a plasma is ignited in thecontainer.

[0081] i) Bonding Agent/Barrier Composite:

[0082] First of all, as in Variant 2, an organic bonding agent layer isapplied, but this time in a thickness of 10 nm with a high HMDSNconcentration.

[0083] This is followed by a rapid gas change to a lower HMDSNconcentration of 1.5%, and an inorganic barrier layer with a layerthickness of 15 nm is applied over the course of 11.4 seconds.

[0084] The coating makes it possible to produce a bonding agent/barriercomposite with a high O₂ barrier improvement factor (O₂ BIF) of 18.7, asrevealed by the following data: the permeation of the uncoated bottle is0.196 cm³/(specimen×day×bar), and that of the coated bottle is below0.0104 cm³/(specimen×day×bar).

[0085] Exemplary Embodiment 4:

[0086] Gradient Layer with Improved Bonding

[0087] A 0.5 l bottle made from polyethylene terephthalate (PET) issimultaneously evacuated to a pressure of 85 mbar on the outside andinitially to a base pressure of less than 0.9 mbar on the inside.Subsequently, a mixture of oxygen and hexamethyldisilazane (HMDSN) orhexamethyldisiloxane (HMDSO) is introduced into the interior of thebottle at a fixed pressure of, for example, 0.4 mbar, and a pulsedmicrowave plasma is ignited. A gradient layer is applied to thesubstrate; one option for production of this gradient layer is, asdescribed in EP 0718418A1, the content of disclosure of which is herebyincorporated in its entirety in the present application, is tocontinuously alter at least one of the parameters pulse length and/orinterpulse period during the layer growth. Another alternative is forthe gradient layer to be produced by a continuous or stepped change inat least one of the coating parameters microwave power, pulse length,interpulse period, oxygen or precursor flow rate. The gradient layerproduces improved bonding combined, at the same time, with a highbarrier action. Gradient layers of this type can also be applied to anyother desired substrate. These gradient layers produced in this way havea stoichiometric or structural variation in a direction perpendicular tothe surface.

[0088] Exemplary Embodiment 5:

[0089] HDPE

[0090] Variant 1

[0091] A hollow body made from high density polyethylene (HDPE), volume70 ml, is evacuated to a pressure of less than 0.1 mbar. Subsequently, amixture of oxygen and hexamethyldisilazane (HMDSN) is passed into thecontainer at a pressure of 0.6 mbar and pulsed microwave energy isintroduced with an pulse power of 2.7 kW. A plasma is ignited and anSiO_(x) layer is deposited with a thickness of a) 80 nm in 70 seconds,corresponding to a deposition rate of 1.14 nm/s, and b) 300 nm in 270seconds, corresponding to a deposition rate of 1.11 nm/s. An uncoatedspecimen has an O₂ permeation of 0.86 cm³/(specimen×day×bar), the 80 nmthick specimen has an O₂ permeation of 0.62 cm³/(specimen×day×bar), andthe 300 nm thick specimen has an O₂ permeation of 0.33cm³/(specimen×day×bar).

[0092] Variant 2

[0093] A hollow body made from high density polyethylene (HDPE), volume500 ml, is evacuated to a pressure of less than 0.1 mbar. Subsequently,a mixture of oxygen and hexamethyldisilazane (HMDSN) is passed into thecontainer at a pressure of 0.3 mbar and pulsed microwave energy with apulse power of 1000 W is introduced. A plasma is ignited, and at a highHMDSN concentration a) a bonding agent layer with a thickness of 20 nmis deposited. A barrier layer with a thickness of 10 nm is applied tothis bonding agent layer over the course of 12 seconds, b) a bondingagent layer with a thickness of 20 nm is deposited. A barrier layer witha thickness of 80 nm is applied to this bonding agent layer over thecourse of 71.2 seconds.

[0094] An uncoated specimen has an O₂ permeation of 3.04cm³/(specimen×day×bar), the specimen produced in accordance with processa) has an O₂ permeation of 0.80 cm³/(specimen×day×bar), and the specimenproduced in accordance with process b) has an O₂ permeation of 0.55cm³/(specimen×day×bar). This results in an O₂ BIF of a) 3.8 and b) 5.5.

[0095] Exemplary Embodiment 6:

[0096] PET Film

[0097] A 100 μm thick PET film is fitted into a receptacle which is thenevacuated. Subsequently, a mixture of oxygen and a) titanium chloride,b) hexamethyldisilazane is passed into the reactor and a pressure of 0.2mbar is set. Thereupon, microwave energy with a pulse power of 11 kW isintroduced into the reactor from one side and a plasma is ignited.

[0098] a) A 100 nm thick TiOx layer is deposited on one side of thefilm. The reactor is then ventilated and the film removed. Measurementof the water vapor permeation in accordance with DIN 53122, Part 1 givesa value of 0.020 g/(m²/day) for the coated film, while an H₂O permeationof 1.96 g/(m²/day) is determined for an uncoated film. The H₂O BIF istherefore 98.

[0099] b) A 100 nm thick SiO_(x) layer is deposited. Measurement of thewater vapor permeation gives a value of 0.4 g/(m²/day) and therefore anH₂O BIF of 4.9.

[0100] Exemplary Embodiment 7:

[0101] PES Film, Coated on Both Sides

[0102] A 25 μm thick film of polyether sulfone (PES) is fitted into areceptacle and the receptacle is then evacuated. Subsequently, a mixtureof oxygen and a) titanium chloride, b) hexamethyldisilazane is passedinto the reactor and a pressure of 0.2 mbar is set. Thereupon, microwaveenergy is introduced into the reactor and a plasma ignited in each casefrom one side.

[0103] a) With a pulse power of in each case 11 kW, a 20 nm thickTiO_(x) layer is deposited on both sides. Measurement of the oxygenpermeation in accordance with DIN 53380-3 gives a value of 15.7cm³/(m²×day×bar) for the coated film, while an O₂ permeation of 940 m³(m²×day×bar) is determined for an uncoated film. The O₂ BIF is therefore60.

[0104] b) At a pulse power of in each case 4 kW, a 100 nm thick SiO_(x)layer is deposited on both sides. Measurement of the oxygen permeationgives a value of 1.51 cm³/(m²×day×bar) and therefore an O₂ BIF of 620.

[0105] Exemplary Embodiment 8:

[0106] A film of 1) polystyrene (PS), 25 μm thick, 2) polycarbonate(PC), 20 μm thick, 3) polyether sulfone (PES), 25 μm thick, 4) highdensity polyethylene (HDPE), 10 μm thick, 5) polypropylene (PP), 30 μmthick and 6) fluorinated ethylene-propylene copolymer (FEP), 25 μmthick, is fitted into a receptacle and the receptacle evacuated.Subsequently, a mixture of oxygen and a) titanium chloride, b)hexamethyldisilazane is passed into the reactor and a pressure of 0.2mbar is set. Thereupon, microwave energy with a pulse power of a) 11 kWfor the production of TiO_(x) and b) 4 kW for the production of SiO_(x)is introduced into the reactor from one side and a plasma is ignited.

[0107] 1a) A 50 nm thick TiO_(x) layer is deposited. Measurement of thewater vapor permeation gives a value of 0.76 g/(m²×day) for the coatedPS film, whereas an H₂O permeation of 91 g/(m²×day) is determined for anuncoated PS film. The H₂O BIF is therefore 120.

[0108] 1b) A 200 nm thick SiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 0.2g/(m²×day) and therefore an H₂O BIF of 455.

[0109] 2a) A 50 nm thick TiOx layer is deposited on one side.Measurement of the water vapor permeation gives a value of 0.5g/(m²×day) for the coated PC film, whereas an H₂O permeation of 11.5g/(m²×day) is determined for an uncoated PC film. The H₂O BIF istherefore 22.

[0110] 2b) A 50 nm thick SiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 0.62g/(m²×day) and therefore an H₂O BIF of 18.

[0111] 3a) A 100 nm thick TiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 3.69g/(m²×day) for the coated PEF film, whereas an H₂O permeation of 234.35g/(m²×day) is determined for an uncoated PES film. The H₂O BIF istherefore 63.

[0112] 3b) A 50 nm thick SiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 4.13g/(m²×day) and therefore an H₂O BIF of 56.

[0113] 4a) A 50 nm thick TiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 1.11g/(m²×day) for the coated HDPE film, whereas an H₂O permeation of 6.63g/(m²×day) is determined for an uncoated HDPE film. The H₂O BIF istherefore 6.

[0114] 4b) A 200 nm thick SiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 1.04g/(m²×day) and therefore an H₂O BIF of 6.3.

[0115] 5a) A 50 nm thick TiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 0.32g/(m²×day) for the coated PP film, whereas an H₂O permeation of 0.42g/(m²×day) is determined for an uncoated PP film. The H₂O BIF istherefore 1.3.

[0116] 5b) A 50 nm thick SiO_(x) layer is deposited on one side.Measurement of the water vapor permeation gives a value of 0.33g/(m²×day) and therefore an H₂O BIF of 1.3.

[0117] 6a) At a pulse power of in each case 11 kW, a 50 nm thick TiO_(x)layer is deposited on one side. Measurement of the water vaporpermeation gives a value of 0.55 g/(m²×day) for the coated FEP film,whereas an H₂O permeation of 3.64 g/(m²×day) is determined for anuncoated FEP film. The H₂O BIF is therefore 6.5.

[0118] 6b) With a pulse power of in each case 4 kW, a 50 nm thickSiO_(x) layer is deposited on one side. Measurement of the water vaporpermeation gives a value of 1.18 g/(m²×day) and therefore an H₂O BIF of3.

[0119] Exemplary Embodiment 9:

[0120] PET Film with Alternating SiO_(x)/TiO_(x) Layers:

[0121] A 23 μm thick PET film is installed in a receptacle and thereceptacle evacuated. Then, the following processes 1) and 2) arecarried out alternately and repeatedly:

[0122] 1) A mixture of oxygen and titanium chloride is passed into thereactor and a pressure of 0.2 mbar is set thereupon, microwave energywith a pulse power of 11 kW is introduced into the reactor from one sideand a plasma is ignited.

[0123] 2) After the TiO_(x) layer has been deposited, the reactor isimmediately flushed with a gas mixture of oxygen andhexamethyldisilazane (HMDSN), and then a plasma is ignited at the samepressure but a pulse power of 4 kW and an SiO_(x) layer is deposited.

[0124] a) Processes 1) and 2) are carried out once and an alternatinglayer comprising 100 nm of TiO_(x) and 100 nm of SiO_(x) is deposited.Subsequently, the receptacle is ventilated and the specimen removed.Measurements of the water vapor permeation of the coated film give avalue of 0.055 g/(m²×day), and measurements of the water vaporpermeation of an uncoated film give a value of 10.87 g/(m²×day). The H₂OBIF is therefore a factor of 199.

[0125] b) Processes 1) and 2) are carried out twice and an alternatinglayer comprising 4 individual layers is then ventilated in thereceptacle and the specimen removed. Measurements of the water vaporpermeation of the coated film give a value of 0.04 g/(m²×day), andmeasurements of the water vapor permeation for an uncoated film give avalue of 10.87 g/(m²×day). The H₂O BIF is therefore a factor of 270.

[0126] Exemplary Embodiment 10:

[0127] A 10 ml bottle made from Topas (COC: cycloolefin copolymer) isfirst of all evacuated on the inside to a base pressure of lower than0.09 mbar. Subsequently, a mixture of oxygen and hexamethyldisilazane(HMDSN) is passed into the interior of the bottle at a pressure of 0.5mbar. Then, pulsed microwave energy with a pulse power of 3.5 kW and afrequency of 2.45 GHz is introduced, a plasma is ignited in thecontainer and the container is internally coated with 125 nm of SiO_(x).Immediately thereafter, the bottle is ventilated and removed.Measurements of the water vapor permeation give a value of 0.14mg/(specimen×day) for the coated bottle, whereas a water vaporpermeation of 0.29 mg/(specimen×day) is measured for the uncoatedbottle. This gives a barrier improvement factor (BIF) of 2. Measurementsof the oxygen permeability give a value of 0.047 cm³/(specimen×day×bar)for the coated bottle and a value of 0.15 cm³ (specimen×day×bar) for theuncoated bottle, and therefore the O₂ BIF is 3.1.

[0128] Exemplary Embodiment 11:

[0129] A 10 ml bottle made from polycarbonate (PC) is first of allevacuated on the inside to a base pressure of less than 0.09 mbar.Subsequently, a mixture of oxygen and hexamethyldisilazane (HMDSN) ispassed into the interior of the bottle at a pressure of 1.0 mbar. Then,pulsed microwave energy with a pulse power of 2.8 kW and a frequency of2.45 GHz is introduced and a plasma is ignited in the container. Theinside of the container is coated with 100 nm of SiO_(x) over the courseof 40.3 seconds, corresponding to a deposition rate of 2.48 nm/s.Immediately thereafter, the bottle is ventilated and removed.Measurements of the water vapor permeation give a value of 2.3mg/(specimen×day) for the coated bottle, whereas a water vaporpermeation of 6.6 mg/(specimen×day) is measured for the uncoated bottle.This gives a barrier improvement factor (BIF) of 2.8. Measurements ofthe oxygen permeability give a value of 0.008 cm³/(specimen×day×bar) forthe coated bottle and a value of 0.158 cm³/(specimen×day×bar) for theuncoated bottle, which means a O₂ BIF of 19.

1. A composite material[[,]] comprising: a substrate material; and atleast one barrier coating on one side of the substrate material, whereinthe at least one barrier coating is a plasma impulse chemical vapordeposition coating, and the at least one barrier coating comprises amaterial selected from the group consisting of: SiO_(x) with 1.7≦x<2;SiO_(x) with 2<x≦2.5; TiO_(x) with 1.7≦x<2; TiO_(x) with 2<x≦2.5;SnO_(x) with 1.7≦x<2; SnO_(x) with 2<x≦2.5; Si₃N_(y) with 3.5<y<4;Si₃N_(y) with 4<y<4.5; Nb₂O_(y) with 4<y<5; Nb₂O_(y) with 5<y<6;Al₂O_(y) with 2.5<y<3; Al₂O_(y) with 3<y<3.5; and any combinationsthereof.
 2. The composite material as claimed in claim 1, wherein the atleast one barrier coating further comprises a material selected from thegroup consisting of: amorphous hydrocarbons, Nb_(x)O_(y) with xε[0,2],yε[0,5], and any combinations thereof.
 3. The composite material asclaimed in claim 1, wherein the substrate material is a plasticsubstrate.
 4. The composite material as claimed in claim 3, wherein theplastic substrate comprises one or more a material selected from thegroup consisting of polycyclic hydrocarbons, polycarbonates,polyethylene terephthalates, polystyrene, polyethylene, polypropylene,polymethyl methacrylate, PES, and any combinations thereof.
 5. Thecomposite material as claimed in claim 4, wherein the polycyclic carbonis COC.
 6. The composite material as claimed in claim 1, furthercomprising at least one barrier coating on a second side of thesubstrate material.
 7. The composite material as claimed in claim 1,wherein the at least one barrier coating has a thickness less than 1000nm.
 8. The composite material as claimed in claim 7, wherein the atleast one barrier coating comprises at least one continuousmonomolecular layer.
 9. The composite material as claimed in claim 8,wherein the thickness is greater than 20 nm.
 10. The composite materialas claimed in claim 1, wherein the at least one barrier coating forms abarrier against substances from the atmosphere and/or substances thatare in direct contact with the composite material and/or are containedin or released from the substrate material.
 11. The composite materialas claimed in claim 1, further comprising an optical or electricalfunctional layer.
 12. The composite material as claimed in claim 11,wherein the optical or electrical functional layer is integrated in theat least one barrier coating.
 13. The composite material as claimed inclaim 1, wherein the at least one barrier coating comprises a gradientlayer.
 14. The composite material as claimed in claim 1, wherein the atleast one barrier coating comprises a stepwise change in stoichiometryand/or structure in a direction perpendicular to the surface of thecomposite material.
 15. The composite material as claimed in claim 13,wherein the at least one barrier coating comprises an alternatingTiO_(x)/SiO_(x) layer.
 16. The composite material as claimed in claim15, wherein the alternating TiO_(x)/SiO_(x) layer comprises analternating TiO_(x)/SiO_(x)/TiO_(x)/SiO_(x)/layer.
 17. The compositematerial as claimed in claim 15, wherein the alternating TiO_(x)/SiO_(x)layer comprises individual layers having a thickness in a range from 5nm to 100 nm.
 18. A process for producing a composite material,comprising: introducing a substrate material into a coating reactor witha gas atmosphere, introducing precursor gases into the coating reactor,generating a plasma in the coating reactor by means of pulses so thatthe precursor gases react with the gas atmosphere, setting at least oneof an oxygen flow rate and a precursor flow rate so that a barriercoating is deposited on the substrate material, the barrier coatingcomprising a material selected from the group consisting of: SiO_(x)with 1.7≦x<2; SiO_(x) with 2<x≦2.5; TiO_(x) with 1.7≦x<2; TiO_(x) with2<x≦2.5; SnO_(x) with 1.7≦x<2; SnO_(x) with 2<x≦2.5; Si₃N_(y) with3.5<y<4; Si₃N_(y) with 4<y<4.5; Nb₂O_(y) with 4<y<5; Nb₂O_(y) with5<y<6; Nb_(x)O_(y) with xε[0,2], yε[0,5]; Al₂O_(y) with 2.5<y<3;Al₂O_(y) with 3<y<3.5; amorphous hydrocarbons, and any combinationsthereof.
 19. The process as claimed in claim 18, wherein the pulses aremicrowave pulses or radio-frequency pulses.
 20. The process as claimedin claim 19, further comprising introducing the microwave pulses orradio-frequency pulses via dielectric windows or antennas.
 21. Theprocess as claimed in claim 19, wherein the microwave pulses are in afrequency range from 90 to 3000 MHz.
 22. The process as claimed in claim19, wherein the radio-frequency pulses are in a frequency range below 90MHz.
 23. The process as claimed in claim 18, wherein the precursor gasescomprise a substance selected from the group consisting of HMDSN, HMDSO,TMS, silane in N₂, TiCl₄, and any combinations thereof.
 24. The processas claimed in claim 18, wherein the gas atmosphere comprises anatmosphere selected from the group consisting of an O₂ atmosphere, an N₂atmosphere, and an N₂+NH₃ atmosphere.
 25. The process as claimed inclaim 18, further comprising altering continuously or in steps at leastone of selected from the group consisting of pulse length, interpulseperiod, microwave power, oxygen flow rate, and precursor flow rate. 26.The process as claimed in claim 18, further comprising using a microwavepower in a range from 300 W to 12 kW to deposit the barrier coating. 27.The process as claimed in claim 18, wherein the pulses have pulselengths of 0.1 to 20 ms, and interpulse periods of 5 ms to 400 ms. 28.The process as claimed in claim 18, further comprising evacuating thecoating reactor after the substrate material has been introduced intothe coating reactor and before precursor gases are introduced.
 29. Theprocess as claimed in claim 18, wherein the substrate material comprisesa hollow body, the process further comprising depositing the coating onan inner side and/or an outer side of the hollow body.
 30. The processas claimed in claim 29, further comprising evacuating the inner side andthe outer side simultaneously prior to the coating, until an externalpressure of less than 200 mbar is reached, and continuing to evacuatethe inner side, down to a base pressure of less than 1 mbar.
 31. Ahollow body, comprising: an inner side; an outer side; and at least oneplasma impulse chemical vapor deposition barrier coating on the innerside and/or the outer side, wherein the at least one barrier coating isa material selected from the group consisting of SiO_(x) with 1.7≦x<2,SiO_(x) with 2<x≦2.5, TiO_(x) with 1.7≦x<2, TiO_(x) with 2<x≦2.5,SnO_(x) with 1.7≦x<2, SnO_(x) with 2<x≦2.5, Si₃N_(y) with 3.5<y<4,Si_(x)N_(y) with 4<y<4.5, Nb₂O_(y) with 4<y<5, Nb₂O_(y) with 5<y<6,Al₂O_(y) with 2.5<y<3, Al₂O_(y) with 3<y<3.5, and any combinationsthereof.
 32. The hollow body as claimed in claim 31, wherein the barriercoating is on the inner side of the hollow body.
 33. The hollow body asclaimed in claim 31, wherein the barrier coating is on the inner andouter sides of the hollow body.
 34. The hollow body as claimed in claim31, wherein the hollow body has a volume from 10 ml to 5000 ml.
 35. Asheet-like substrate comprising: a first side; a second side; and atleast one plasma impulse chemical vapor deposition barrier coating onthe first and/or the second side, wherein the at least one barriercoating is a material selected from the group consisting of SiO_(x) with1.7≦x<2, SiO_(x) with 2<x≦2.5, TiO_(x) with 1.7≦x<2, TiO_(x) with2<x≦2.5, SnO_(x) with 1.7≦x<2, SnO_(x) with 2<x≦2.5, Si₃N_(y) with3.5<y<4, Si₃N_(y) with 4<y<4.5, Nb₂O_(y) with 4<y<5, Nb₂O_(y) with5<y<6, Al₂O_(y) with 2.5<y<3, Al₂O_(y) with 3<y<3.5, and anycombinations thereof.
 36. The sheet-like substrate as claimed in claim35, wherein the sheet-like substrate defines a display cover.